expand with statement to avoid invoking null context managers.

Author: kristjanvalur

redis/asyncio/connection.py

@@ -895,12 +895,26 @@ async def read_response(
     ):
         """Read the response from a previously sent command"""
         read_timeout = timeout if timeout is not None else self.socket_timeout
-        lock_ctxt = self._lock if with_lock else nullcontext
         try:
-            async with lock_ctxt, async_timeout.timeout(read_timeout):
-                response = await self._parser.read_response(
-                    disable_decoding=disable_decoding
-                )
+            if with_lock:
+                if read_timeout is not None:
+                    async with self._lock, async_timeout.timeout(read_timeout):
+                        response = await self._parser.read_response(
+                            disable_decoding=disable_decoding
+                        )
+                else:
+                    async with self._lock:
+                        self._parser.read_response(disable_decoding=disable_decoding)
+            else:
+                if read_timeout is not None:
+                    async with async_timeout.timeout(read_timeout):
+                        response = await self._parser.read_response(
+                            disable_decoding=disable_decoding
+                        )
+                else:
+                    response = await self._parser.read_response(
+                        disable_decoding=disable_decoding
+                    )
         except asyncio.TimeoutError:
             if timeout is not None:
                 # user requested timeout, return None